1. Field of the Invention
This invention relates to an apparatus for amplifying luminance on the surface of an illuminant and also concerns an apparatus for improving brightness in images looked at through X-ray examination apparatuses, images indicated on TV Braun tubes and discharge type display panels, or symbols indicated on display panels by light emitting diodes.
2. Description of the Prior Art
In the prior art indirect X-ray photographing apparatuses for medical services, the X-rays transmitted through a human body are imaged on a fluorescent screen as a visible image which is in turn photographed. Recently, there is stricter standards about X-ray irradiation doses which remarkably restrict X-ray irradiation for human bodies. If the X-ray irradiation is decreased, brightness in images formed on a fluorescent screen would be reduced. This leads to such a problem that it is difficult to make a diagnosis based on X-ray photographs. On the contrary, if the image brightness is increased by changing the construction of the fluorescent screen so as to overcome such a problem, the resolving power would be reduced. It is therefore desired that the image brightness is increased without any reduction in resolving power.
On the other hand, there is a remarkably large advance in the field of discharge type plane display panels as in wall type television receivers. Such plane display panels comprise a matrix which is provided with a substrate including dotted fluorescent layers disposed thereon corresponding to R.G.B. and ultraviolet illuminant elements located behind the substrate for illuminating the respective separated dots. There is presently a problem in that the luminance in each dot is in low level. It is difficult to increase the luminance under various limitations as in construction of the illuminant element matrix.
It is also desired that electric power is less consumed in the field of LED displaying devices which can be used in small-sized electronic computers. However, if the electric supply is simply decreased, the brightness in displays would be reduced resulting in another problem.